I looked into this about 5 years ago. Idle is not user adjustable and the 92 is factory set to idle very slow about 800 to 900 rpm. I think it is computer controlled. Incorrect sir. Go have a cold one. Reconnect the battery and start it w/o touching anything. Allow it to warm at idle and then move the trans selector amoungst all the trans positions several time for several seconds each to allow it to relearn it's odle paramaters. Drive it around town a few miles and see if all is well. If not, there are some other things that.
Surging idle, running rich, lunging at stopsWelcome to FordTruckClub.netWelcome to FordTruckClub.net, the internet's premier Ford truck community! You are currently viewing our boards as a guest which gives you limited access to view discussions and access other forum features. By joining our free online community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple, and absolutely free so please,!Forgot your password?. Hey guys, been scratching my head on this and need y'alls input before I start throwing parts at it.It seems I have developed a Surging idle.
It will drop real low almost to the point of stalling, catch itself and rev back to normal. It will do this for about a minute to a minute and a half after start up.Driving it, it is fine. Normal acceleration and cruising at any speed.Sitting at a stop and in gear it will lunge forward against the brakes.Have done the KOEO, KOER, and CBST. With nothing showing.My thoughts are either O2, TPS, or IAC.O2 isn't very old at all and I have not purchased a new IAC or TPS since owning either the 90 or 94.Any thoughts appreciated.Cleaned IAC, no change.
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Hi all, Rick Baran from Burlington Washington here.my 87 Bii just got it's new motor, courtesy of a HORRIBLE oil change mishap at Sears. They neglected to put an oilfilter gasket on, and I made it about 1/2 mile down the freeway.!! Anyways, the 2.9 is factory fresh, but it's surging significantly during idle when cold.It'll surge up to say 1500, then down to maybe 800.up to 1500, down to 650.up to 1500, down to stop. Once it's warm it's just fine, and if I hold my foot on the accel keeping it at 1200 or so it's fine.Any idears? The guys at Skagit Ford have checked all the sensors and state they're good.Rick. MY 2.9 used to do thatIAC Cleaning/Testing:The IAC is usually a cylindrical unit attached to the upper intake manifold.
Found on drivers side of intake manifold. This unit is electrically controlled by the computer, and allows air to flow into the intake at idle, bypassing the throttle plate. The extra air is accompanied by extra fuel to bring the idle up to proper speed, and when cold, allows a high idle condition. These units may become dirty, and need cleaning. Many idle and stalling issues tend to be blamed on these units. Cleaning is achieved by removing the electrical connector, and two screws holding it on.
Once off of the vehicle, clean with throttle body cleaner (or a good carburetor cleaner). Continue cleaning until unit is clean, like new; reinstall unit. This is also a good time to clean the intake, and EGR ports (if applicable).Testing may be achieved by bringing the engine to operating temperature, noting the idle speed (should be within spec). Unplug the unit’s electrical connector, and the idle should drop to about 650 RPM. When the unit is reinstalled, it should return to normal idle speed. If the vehicle does not idle at proper RPM (too low), there are no vacuum leaks, and the TPS calibration is correct, than the unit is most likely faulty.i would start with the IAC and see if it helps, but remember it takes unhooking the battery to reset the codes in the computer or approximatly 100 starts of a motor.
My 2.9 used to do that, and even though you have a new motor chances are they used the old throttle body and all the fuel injection system from beforeif cleaning the IAC and resetting computers codes doesnt help then try the throttle positioning sensor. BUT CLEAN THE IAC FIRST.to test it warm truck up turn key to on position with motor off, the center wire to ground should read 0.9 volts to ground.if not adjust screw at lower part untill it does. If adjusted with idle correct, but this is unlikely your surging problem it is usually accustome to the IAC bieng dirty. The IAC was replaced, courtesy of Skagit Ford. I still have the problem.
I'm going to treat the intake with SeaFoam today and I'll let everyone know if this improves performance. I also checked the IAC voltage and idle-checked the engine with the IAC unplugged.normal. So I'm going to move onto the MAF sensor next.Although the guys at Skagit did reuse the intake manifold, they cleaned it very thoroughly.
I'll keep looking for vacuum leaks also.How would I check for the correct vacuum connection on the Fuel Pressure Regulator?Rick.